I'm wondering if anyone has seen something similar or has any idea of what to test to further isolate the problem. What I'm observing is that my LAN connection kind of freezes during large internet downloads. And afterwards Windows 10 won't shut down or reboot timely, but instead it needs like 15 minutes to recover.

The setup is:

Windows 10 PC <-> fritzbox 6690 router <-> Vodafone internet provider

The PC mainboard is a ASUS ROG Strix B550-F Gaming with an Intel I225-V 2.5 GBit/s port. I have confirmed through various burn-in tests that the system itself is rock stable. And the exact same machine has previously been in use with a different routing setup and never had any issues. Also, iperf against various LAN destinations (including the internet router) returns 1.1 GBit/s and is stable for hours.

Through various speed and internet tests over WiFi, I have also confirmed that the fritzbox router has a stable internet connection. There is a bit of packet loss, but at <0.1% I believe it is small enough to ignore.

So the PC can download files at >1 GBit/s from the router and from other PCs on the cable LAN. And that never causes any stability issues. But downloading files through the router from the internet causes the PC to lose its cable network connection.

If I afterwards turn on WiFi on the PC, I can connect to the router and download the same file just fine. So the "crash" appears to not affect the router or the internet connection at all. Instead, it looks like some internal state inside Windows 10 is crashing. That would also be in line with the observation that after such a "crash" happened, Windows does not shut down normally anymore.

Sadly, the Windows Event Log doesn't contain anything useful related to the event. Also, the error log on the router side also doesn't mention anything. The only indication that the crash occurred is that Windows loses the DHCP settings. (But setting a static IP and route also doesn't help.)

The thing that irks me is that the same LAN port is rock stable when downloading things from within the same LAN. And it was rock stable before I moved it to its new location, so previously it could download files through a (slightly different model) fritzbox router just fine.

So there seems to be something unique about this specific internet connection which causes the Intel I225-V driver to crash. But it's not crash-inducing enough to crash the router, it only crashes this PC. Also, small or slow downloads don't trigger the bug. Only large and fast downloads do.

How would you measure that?

(I started toying around with Wireshark, but looking through > 1 GB of data transfer is exhausting and I'm not really sure what I am looking for. Any ideas?)

1 Answer 1


There are a lot of things this could be. I would try the following

  • Scan for viruses
  • check for NIC driver update
  • another patch cord
  • Create a new user and log in as that user to test (if it works you know the issues is in your profile)
  • Boot off the ubuntu install usb stick pick try then test (if it works then backup your data and do a Windows Refresh)

I hope this helps

  • 1
    Given these symptoms, I strongly look at the NIC hardware or driver being a problem.
    – mfinni
    Apr 11, 2023 at 6:27
  • Thank you, kind stranger for pointing out the obvious. It appears I was missing the forest for the trees. ^^ Replacing the NIC hardware fixed all issues.
    – fxtentacle
    Apr 15, 2023 at 9:52

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .